Prefabricated taphole assembly for metallurgical furnaces



y 4, 1967 A. E. FINN 3,329,420

PREFABRICA'IED TAPHOLE ASSEMBLY FOR METALLURGICAL FURNACES Filed Oct. 5, 1966 2 SheetsSheet 1 /A VA 70/ ALFRED E. FINN ITTO/P/VE) A. E. FINN July 4, 1967 FOR METALLURGICAL FURNACES PREFABRICATED TAPHOLE ASSEMBLY 2 Sheets-Sheet Filed Oct. 1966 WVWTO/P. ALFRED E. FIN/V 1/ United States Patent PREFABRICATED TAPHOLE ASSEMBLY FOR METALLURGICAL FURNACES Alfred E. Finn, Pittsburgh, Pa., assignor to Harbison- Walker Refractories Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct. 5, 1966, Ser. No. 584,544

9 Claims. (Cl. 26642) It has been standard practice in the steel industry to form tapholes particularly in the basic oxygen furnace,'

from dead burned magnesite refractories having a high MgO content, since magnesite is one of the best basic refractories known for contact with molten metal in basic steelmaking furnaces, and for resisting the high temperatures and chemical attack which occur in the operation of such furnaces. r

Heretofore, tapholes for basic oxygen furnaces, basic open hearths, electric furnaces, etc, have been formed in a variety of ways. One such mode of installation was by ramming successive layers of magnesite grain about a steel pipe passing through the taphole opening in the furnace shell and opening into the furnace chamber until the taphole area was completely filled with the refractory. However, owing to the structure and location of the tapholes, it was found difiicult to ram all of the interstices or. crevices in the taphole area and to obtain high densities thereby. The same difficulties were encountered in completely vibration casting the taphole area. There will be noted subsequently from the drawing that the taphole area, if located in the cone section of the furnace, as in the basic oxygen furnace, is not an ideal place to endeavor a vibration cast taphole. Another objection to the above method is that vibration casting mixes typically contain between 7 and 8% of water, and the water must be removed during burning. This requires higher temperatures and a relatively long. burning schedule which extends the down-time of the vessel. It is important that the refractory employed for the taphole and the technique used to install it be compatible with the burn-in schedule of the refractory lining of the furnace since it comprises the bulk of the furnace.

Accordingly, there has been a long existing need in the art for reducing the time required to install a basic steelmaking furnace taphole; for eliminating the lack of uniformity inherent in rammed and vibration cast tapholes; and for significantly reducing the maintenance and repair costs and furnace down-time involved for delays in taphole area repairs in the operation of the basic steelmaking furnaces.

In my application Ser. No. 488,386, now United States Patent No. 3,295,845, filed Sept. 20, 1965, entitled Basic Oxygen Steelmaking Vessels, and assigned to the present assignees, I dis-closed and claimed a prefabricated taphole assembly for use in inclined tapholes. This application is closely related thereto.

Therefore, it is an object of the present invention to provide a novel, integral, uniform, dense, highly refractory inclined taphole in a basic steelmaking furnace which substantially reduces the time heretofore required for installing or replacing tapholes.

Another object of the invention is to provide a prefabricated, highly refractory taphole suitable for use in a basic oxygen furnace which is compatible with the burn ing schedule of the refractory lining in the remainder of the furnace.

Other objects of the invention will be apparent hereinafter.

3,329,420 Patented July 4, 1967 In the drawings:

FIG. 1 is a perspective view, partly broken away, of a basic oxygen furnace, particularly showing the taphole side of the furnace;

FIG. 2 is a perspective view partly cut away of a prefabricated taphole according to the present invention.

In accordance with the present invention, there is provided a prefabricated quadripartite taphole assembly suitable for use in metallurgical vessels of the type having an outer metal shell, a refractory lining adjacent the shell and an inclined taphole. The assembly is composed of mated refractory brick shapes, the individual shapes have generally opposed face, side and end surfaces and are amenable to contiguous mating simultaneously with two other shapes in the assembly. One face and side surface of each brick shape terminates short of a common edge and a concave surface extends between the terminus of the side and face surfaces and intersects the opposed ends. Each of the shapes at the concave surface defines a segment of a taphole in the quardipartite assembly. Each brick shape is matched with two other shapes in the assembly at the concave surface so that the assembly of brick shapes defines a cylindrical taphole opening passing entirely therethrough.

Referring to FIG. 1, there is shown a basic oxygen furnace 10 consisting of an outer metal shell 12, a shell protective brick lining 14 in contact with the inside surface of the shell and a brick working lining 16. The vessel is constructed of three major zones, the bottom zone 18, the barrel zone 20, and the cone section 22. The bottom zone is dish shaped and of upwardly opening concave configuration. The brick 23 in the bottom zone terminate at the barrel zone 20 with their face surfaces inclined from the bottom upwardly to the cone section zone. The working lining brick 14 in both the barrel and the cone section zones are disposed so that their face surfaces are in the horizontal plane. The cone section zone, having a taphole area 26, extends upwardly and terminates in the form of a mouth 28 at the top of the vessel. The cone section zone is of downwardly opening truncated crosssectional configuration.

Disposed in the taphole area of the vessel is a taphole assembly 30 according to the present invention (best shown in FIG. 2). The taphole assembly 30 is composed of refractory brick shapes 32, 34, 36 and 38.The individual brick contain opposed face, side and end surfaces.

One face surface 32a, 34a, 36a and 38a and one side surface 32b, 34b, 36b and 38b terminate short of a common edge (which would exist if the face and side surfaces were projected until they met). Between each short face and side surface, at the terminus thereof, there ex tends a concave surface 32c, 34c, 36c and 380, which intersect the opposed ends of each shape. Each concave surface defines a segment of a taphole in the quadripartite assembly 30. The shapes are disposed so that correspond ing face and side surfaces are mated so that the assembly of brick shapes defines a cylindrical taphole opening passing through the assembly. That is, an a surface is mated with a similar a surface on an adjacent brick and the b surface mated with a corresponding surface on an adjacent brick. The surfaces that are mated on each brick are actually mirror images of a corresponding adjacent brick surface.

All of the shapes are key-shaped, adaptable to the circular contour of the cone section of the basic oxygen furnace. By definition, key brick are brick shapes having six plain faces (two sides, two edges and two ends), in which two faces (the edges) are inclined toward each other and one of the end surfaces is narrower than the other. In addition, each of the brick shapes in the assembly are preferably biased in a manner such that each brick is mated with a shape biased toward the taphole opening and simultaneously with one biased toward the furnace interior. This biasing of each shape is necessary where a concave surface of constant circumference is desired while providing the inclination required of the taphole. For example, in order for the concave surfaces 34c and 36c to have a constant circumference between opposed ends, and provide an inclined taphole when assembled, the shape 34 should be biased toward the opening while shape 36 is biased away from the opening.

In another embodiment of the invention, the face surfaces 32a, 34a, 36a and 38a may be substantially rectangular (i.e., the shapes are not biased). However, in order to obtain an inclined cylindrical opening in the assembly, it is necessary that the circumference of each of the concave surfaces 32c, 34c, 36c and 380 be greater at one end than at an opposed end. For instance, if the face surfaces 34a and 36a are substantially rectangular, then the concave surface 340 will be of larger circumference where it intersects end 34d than at the opposed end. Correspondingly, the concave surface 36c will be of smaller circumference at end 36d than at the opposed end.

The end surfaces of each brick are unidirectionally inclined to be side surfaces thereof to conform in contour to the truncated cone section zone. Each of the brick could be of a true parallelogram cross sectional configuration depending upon the inclination of the cone section zone.

While the drawings show a single prefabricated taphole assembly, other assemblies could be disposed adjacent thereto with the cylindrical taphole opening in alignment therewith to provide an elongated opening. The number of taphole assemblies required, will, of course, be dependent upon the size of the brick shapes and the size of the vessel in Which they are utilized.

In practice, the taphole assembly of the present invention can be placed in the basic oxygen vessel shown in FIGURE 1, readily and with a minimum of labor. Each of the mating faces of the refractory brick 32, 34, 36 and 38 may be clipped in a mortar slurry, if desired, before assembly thereof. After the brick in the barrel zone are stacked up to the cone section zone and the taphole opening, the taphole assembly is merely laid and mortared to the terminal brick in the barrel zone or separated with a minimum amount of rammed fill so that the continuous inclined taphole is in alignment with the taphole opening 50 through the furnace shell. Then the cone section zone, in the taphole area, is laid in the normal manner.

As shown in FIG. 1, the inclined end surfaces of the brick are contiguous with the shell protective lining. The remainder of the taphole opening may be readily fabricated by inserting a pipe in alignment with the prefabricated inclined taphole and then filling around the pipe with a monolithic refractory material from exterior the furnace.

Further, the taphole opening in the assembly 30 may be provided with a female socket 40 which is formed in the ends adjacent the taphole. The socket may conveniently be obtained by preforming a portion thereof on an end surface of each shape conforming in contour to the concave surface. The cylindrical opening at the taphole accordingly will be counter sunk. The socket is then mated with one end of the pipe to insure continuous alignment and connection therewith.

The individual brick of the taphole assembly could be composed of highly refractory, dead burned magnesite processed to high densities as are the remainder of the brick lining the vessel; so that the burnin schedule of the taphole would be similar to the burnin schedule of the remainder of the lining and the problems heretofore encountered with differently fabricated tapholes would not occur. However, it is not intended that the taphole construction of present invention be limited to magnesite shapes. Other basic refractories conventionally used in the basic oxygen furnace are suitable.

While the invention has been described with reference to basic oxygen steelmaking vessels, it should not be limited thereto, as the prefabricated taphole asembly of the type shown could be utilized with other vessels such as open hearths, electric furnaces, and the like.

Having thus described the invention in detail and with sufficient particularity as to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims:

I claim:

1. A prefabricated quadripartite taphole assembly suitable for use in metallurgical vessels composed of mated refractory brick shapes, each shape having generally 0p posed face, side and end surfaces and being amenable to contiguous mating simultaneously with two other shapes in said assembly, one face and side surface of each brick shape terminating short of a common edge, there being a concave surface extending between the terminus of said face and side surface, which intersects said opposed ends, each of said brick shapes at said concave surface defining a segment of a taphole in said quadripartite assembly, each brick shape being mated with two other brick shapes in said assembly at the concave surface so that the assembly of brick shapes defines a cylindrical taphole opening passing entirely therethrough.

2. The assembly of claim 1 in which the end surfaces of the individual brick in the taphole assembly are unidirectionally inclined to the side surfaces thereof.

3. The assembly of claim 1 in which each of the brick shapes is a parallelogram in cross-section but having sloped ends and in which each brick shape at its mated surface is a mirror image of the adjacent mated brick surface.

4. The assembly of claim 1 in which the circumference of the concave surface is greater at the intersection of one opposed end than at the other end for each brick shape.

5. The assembly of claim 1 in which the circumference of the concave surface for each brick is constant between opposed ends.

6. In metallurgical vessels of the type having an outer metal shell, a refractory lining adjacent the shell and an inclined taphole, the improvement comprising at least one prefabricated, quadripartite taphole assembly opening from the vessel interior to the taphole, composed of mated refractory brick shapes, each shape having generally opposed face, said and end surfaces and being amenable to contiguous mating simultaneously with two other shapes in said assembly, one face and side surface of each brick shape terminating short of a common edge, there being a concave surface extending between the terminus of said face and side surface, which intersects said opposed ends, each of said brick shapes at said concave surface defining a segment of a taphole in said quadripartite assembly, each brick shape being mated with two other brick shapes in said assembly at the concave surface so that the assembly of brick shapes defines a cylindrical taphole opening passing entirely therethrough.

7. The vessel of claim 6 which is a basic oxygen converter vessel of the type having a generally circular, open topped barrel zone and a downwardly opening truncated cone section zone superposed thereover and the taphole assembly is disposed in the cone section zone.

8. The vessel of claim 6 in which all the shapes in the taphole assembly are biased and each brick in the assembly is mated with a shape biased toward the taphole and a shape biased toward the vessel interior.

9. The vessel of claim 6 in which there are two taphole assemblies disposed in contiguous contact with the cylindrical taphole openings being in alignment to provide an elongated taphole opening.

(References on following page) 5 6 References Cited 3,084,924 4/ 1963 Morlock 266-41 3 148 238 9/1964 Willenbrock 263-446 X UNITED STATES PATENTS 3,153,110 10/1964 h 26641 Re. 25,528 3/1964 Hall 266-41 S al 393,136 11/1888 Young 26641 5 J. SPENCER OVERHOLSER, Primary Examiner.

1,821,175 9/1931 Cushing 26641 

1. A PREFABRICATED QUADRIPARTITE TAPHOLE ASSEMBLY SUITABLE FOR USE IN METALLURGICAL VESSELS COMPOSED OF MATED REFRACTORY BRICK SHAPES, EACH SHAPE HAVING GENERALLY OPPOSED FACE, SIDE AND END SURFACES AND BEING AMENABLE TO CONTIGUOUS MATING SIMULTANEOUSLY WITH TWO OTHER SHAPES IN SAID ASSEMBLY, ONE FACE AND SIDE SURFACE OF EACH BRICK SHAPE TERMINATING SHORT OF A COMMON EDGE, THERE BEING A CONCAVE SURFACE EXTENDING BETWEEN THE TERMINUS OF SAID FACE AND SIDE SURFACE, WHICH INTERSECTS SAID OPPOSED ENDS, EACH OF SAID BRICK SHAPES AT SAID CONCAVE SURFACE DEFIN- 